Using Long-Term Historical Meteorological Data for Climate Change Analysis in the Carpathian Region

Abstract

In this study, we consider the historical climatological time series available in the meteorological yearbooks of the Royal Hungarian Central Institute of Meteorology and Earth Magnetism, first published in 1871. Data quality improvement of historical data includes the homogenization process with outlier checks and data gap filling by applying the MASH software. We investigated 13 stations from the Carpathian Region having the most complete monthly temperature and precipitation time series for the period of 1871–1918 and 8 stations with fog observations (1886–1916). First, statistical tests were conducted to compare the main statistics of the historical datasets (1871–1918) with current data (1971–2020). The sources of the current data are the National Meteorological Administration of Romania and the European Climate Assessment & Dataset. The results show significant changes between the two periods. In the whole region, the mean temperature in the last five decades (1971–2020) was 0.77 °C higher than in 1871–1918. Changes in the frequency of foggy situations were also detected. On an annual scale, in the last 31-year period (1990–2020), the number of foggy days increased by 16.2 compared with 1886–1916. Even if some local trends can be detected in the historical periods (e.g., Cluj-Napoca), significant changes are much more characteristic in the recent period.

Extreme Events Analysis Using LH-Moments Method and Quantile Function Family

“…The series is homogeneous and the verification was completed with the von Neumann test [44]. To check the homogeneity, MASH v3.03 software can also be used, which was successfully applied in the area of the Pannonian basin [45].…”

Changing Water Cycle under a Warming Climate: Tendencies in the Carpathian Basin

“…An earlier study by Domonkos [55] already detected a significant drop of annual precipitation totals in the 20th century based on aggregated monthly data. Ilona et al [51] also revealed significant changes in the aggregated values of precipitation by comparing historical (1871-1918) and recent (1971-2020) periods. At lowlands, the drop in precipitation totals is larger than 20% during spring and autumn seasons.…”

“…A shift in the distributions is observed only at a few stations. Note that significant trends were not really detected either in the historical data or in recent decades; the latter is somewhat surprising [51]. Lakatos et al [56] analyzed sub-daily precipitation statistics in the region.…”

“…Clear trends were not really observed; instead, the temporal behavior exhibited firm site dependence [50]. However, Ilona et al [51] collated historical fog records for 1886-1916 with recent data for 1990-2020. While decadal trends were not significant, the mean number of foggy days in a year increased by 16.2 d during the recent three decades compared to the turn of the nineteenth century [51].…”

Homogenization and interpolation of relative humidity hourly values with MASH and MISH software

“…So with MASH, we have a temporally representative database, but not yet a spatially representative database (Ilona et al, 2022; Izsák et al, 2022; Venema et al, 2012). So the next step is to ensure spatial representativity: we interpolate the values to a dense regular grid network and can then report on the climate and its possible changes over the whole country.…”